A mitochondrion is an organelle found in most eukaryotic cells. The mitochondrion has its own DNA, i.e. mitochondrial DNA (mtDNA), independently of the nuclear DNA.
The most prominent roles of mitochondria are to produce ATP, the intracellular source of energy. ATP is produced from the electron transport chain using NADH and FADH2 produced in the mitochondrial matrix via the TCA cycle. Thus produced ATP is used to activate various biosynthesis and metabolism processes demanding energy.
Also, mitochondria can transiently store calcium ions, which are important in intracellular signal transduction, in the matrix and release them to the cytoplasm when they are needed. Further, mitochondria are known to play central regulatory roles in apoptosis, cellular proliferation, cellular metabolism, and so forth.
Mitochondrial DNA is relatively susceptible to damage since it lacks its own repair mechanism unlike nuclear DNA and is free from the histone protein for protecting the DNA. It is known that the damage to the mitochondrial DNA is closely related to the onset of mitochondrial diseases. By degrading the function of mitochondria, it results in reduced synthesis of ATP, the source of energy necessary for cellular activities, and causes various diseases.
Chitosan is used in various fields, including flocculants for wastewater treatment, adsorbents for heavy metal removal, functional foods, ion exchange agents, and medical products. It is known that these functions are greatly affected by the molecular weight and deacetylation of chitosan.
Recently, it was reported that chitin, chitosan and their derivatives have decholesterolization activities of adsorbing or excreting bad cholesterols accumulated in the body, anticancer activities of suppressing proliferation of cancer cells, and blood pressure-lowering effects by adsorbing blood pressure-increasing chloride ions and thus reducing their absorption and excreting them out of the body. Further, it was known that they facilitate proliferation of useful intestinal bacteria and activate cells. In addition, they show various physiological activities, including blood sugar control, liver function improvement, excretion of heavy metals and pollutants, and the like. Thus, they are studied as valuable substances in the biomedicine industry.
Although chitooligosaccharides are widely used in health foods and general foods, researches about their function are insufficient. Korean Patent Publication No. 2005-0104910 discloses the function of chitooligosaccharide as an inhibitory material of the lectin-type oxidized LDL receptor 1 (LOX-1) gene in oxidized low-density lipoprotein (oxLDL), effective for prevention of arteriosclerosis. And, Korean Patent Publication No. 2005-0091354 discloses the function of chitooligosaccharide as an inhibitory material of expression of the PPAR gene which is involved in cholesterol homeostasis regulation, fat cell differentiation and fat cell synthesis as a key factor in lipid metabolism.